The Western Sydney hailstorm 2007 / State Emergency Service.

On the afternoon of Sunday 9 December 2007, one of a number of weak thunderstorms west of Sydney developed into an intense supercell thunderstorm. A supercell is a particularly long-lived, powerful and destructive form of thunderstorm. The storm tracked northeast from near Warragamba to cross the coast near Palm Beach; it was at its most intense between Blacktown and Hornsby. In the space of an hour, cricket ballsized hail and strong winds damaged thousands of homes and commercial premises, tens of thousands of vehicles, dozens of warehouses and car yards, and numerous schools, hospitals and government buildings. Thirty women were injured and one taken to hospital with chest pains when the storm tore through an outdoor tea party at Kemps Creek. Insured property losses amounted to $470 million. Some houses were so badly damaged that residents had to be evacuated and allocated short-term accommodation in motels. Blacktown City Council and Baulkham Hills Shire Council buildings and vehicles were extensively damaged. A total of 550 NSW Department of Housing dwellings were directly affected by the hailstorm and 87 buildings in ten government schools required roof repairs to the tune of $5 million. This was the most significant storm to affect metropolitan Sydney since the eastern suburbs hailstorm of April 1999, and one of the most costly on record. It inflicted more damage in the Blacktown region than any previous event in the Blacktown State Emergency Service?s 50-year existence. Blacktown, Penrith, Baulkham Hills and Hornsby local government areas were declared natural disaster areas. As the ?combat agency? for storms in NSW the NSW State Emergency Service (SES) played a lead role in the emergency response to this event. The first weeks of the main response operation involved teams from all 17 NSW SES Regions plus the ACT SES. NSW Fire Brigades also deployed up to 15 strike teams per day, primarily Hazardous Materials units dealing with the many damaged asbestos roofs. Rural Fire Service (RFS) teams helped with doorknocking and undertook ground level work within combined SES-RFS teams to free up SES personnel to work on roofs. By the second week more than 220 teams were operational each day, with more than 1,000 personnel in the field at a time. By the conclusion of the main operation on 19 December approximately 6,000 Requests for Assistance had been dealt with across the region. The response operation was complicated by the wet and windy conditions that continued through the summer. In addition to the main response and on-going revisits, there were four identified storm operations in the region in January and one in February. Overall the SES was operational in the Sydney Western Region continuously from 9 December 2007 to mid-March 2008 and completed over 8,000 jobs. While this hailstorm caused considerable property damage and disruption to peoples? lives, it is not the most severe on record for the Sydney region. Without a doubt, larger and more damaging hailstorms are possible in Sydney and will certainly occur in the future. Climate change may also play a role, with some studies suggesting global warming will increase hail risk in Sydney; although this projection is currently far from definitive. The emergency response to the Western Sydney hailstorm was a complex operation involving many SES resources from around the state, close liaison with other emergency response agencies as well as innovative use of GIS forward mapping support, combined agency teams and airborne reconnaissance. The utility of these innovations and the experiences of personnel involved in this challenging response operation will feed back into planning processes to enable the SES to maintain a cycle of continuous improvement, enhancing its ability to respond effectively to future severe hailstorms in NSW. A report.